1. Field of the Invention
The invention relates to a commercial (CM) detection apparatus that detects commercials and also relates to a video playback apparatus that utilizes the commercial detection apparatus.
2. Description of Related Art
Others have disclosed technologies that evaluate image and audio content to detect commercials. An example of this method is: analyzing contents of an audio signal, detecting silent segments via comparison with set threshold, and determining a segment between silent segments as a commercial if the period of time is equal to a commercial time period (e.g., fifteen seconds or thirty seconds).
Japanese Laid-Open Publication No. 2002-247516 describes a method of detecting commercial segments and recording without the commercial segments or detecting commercial segments and playback without the commercial segments. The commercial segments are detected between the silent segments. In accordance with this method, if there is a fifteen second period of a silent segment in the main program, the silent segment is determined as a commercial.
Additionally, a scenario exists where a silent segment in the boundary of the main program and a commercial extends beyond several seconds. In this scenario, if a transition time from continuous sound to silent or a transition time from silent to continuous sound for a start time or an end time of the silent segment or its median time is used, commercials might not be detected because the time span between the silent segments is not equal to the commercial time.